1. Field of the Invention
The present invention relates to an improved method for bone histomorphometry and an apparatus suitable therefor. More specifically, the present invention relates to a bone histomorphometry method and a bone histomorphometry apparatus capable of evaluating the respective regions of calcified bone, osteoid and bone marrow cavity constituting bone. Such bone histomorphometry is extremely important for grasping the state of disease of bone in metabolic bone diseases such as osteoporosis and osteomalacia and confirming the therapeutical effect of such disease.
2. Description of the Related Art
Bone is always repeating bone absorption and bone formation, and this metabolism cycle of bone is unbalanced in metabolic bone diseases. For example, in senile osteoporosis, the former surpasses the latter, whereby a reduction in bone amount is brought about. On the other hand, in osteomalacia, calcification is obstructed during bone formation, whereby bone formation is stopped at the stage of the bone substrate to increase the bone tissue not calcified, namely osteoid.
Accordingly, diagnosis of the dynamic state of bone in such diseases, namely the balance in the metabolism cycle, becomes important, but there is no efficient method according to the bone histomorphometry in which the test specimen obtained by bone biopsis is measured by microscopic observation. In such a measurement, important indexes may include proportions of bone amount, calcified bone amount, osteoid amount occupied in unit volume of bone (namely unit area in specimen), or surface areas thereof (namely circumferential lengths of the respective regions in specimen) and the like. As the measuring method practiced at present, there have been employed, for example, the hit point method in which microscopic observation is conducted with an eyeglass having a grating-shaped mark, and the points where the gratings cross the respective portions of test specimen are counted with the naked eye, or the semiautomatic method in which the image is traced with a digitizer (i.e., coordinate inputting device), but these methods both require enormous amounts of time and labor and, therefore, even if utilizable in the field of research, they are far from efficient in providing evaluation results for general clinical purposes.
Particularly, generally speaking, bone is not homogeneous, and its form is different even in the same bone specimen depending on the site to be evaluated. For this reason, to enhance the precision and reproducibility of an evaluation, it is necessary to take a large number of measurement sites of, for example, 50 fields of sight, to obtain the evaluation results for the respective sites and obtain an average value thereof. Also, in this sense, it may be said to be indispensable that a further spread of the effective bone form measurement be made to efficiently perform an evaluation at the respective portions.